Microbiological Quality and Safety of Commercially Produced Sausages in Addis Ababa
No Thumbnail Available
Date
2006-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
The microbiological quality and safety of emulsion type small diameter (frankfurter)
and large diameter (mortadella) sausages purchased from different supermarkets in
Addis Ababa, Ethiopia, were investigated between November, 2004 and December,
2005. A total of 210 sausage samples consisting of 120 small diameter (30 each of
pork, beef, veal and chicken) and 90 large diameter (30 each of pork, veal and chicken
mortadella) sausage samples were included in the study. The majority of sausages had
pH values above 6.00 with mean values ranging between 6.11 and 6.33. The moisture
content values of small diameter sausages ranged between 32% and 46% and those of
large diameter sausages ranged between 31 % and 63%.
With regard to the microbial load of small diameter sausages, more than 53% of pork,
87% of beef, 57% of veal and 40% of chicken sausage samples had aerobic
mesophilic counts 2:log 5 cfu/g. Enterobacteriaceae were frequently encountered in
these sausage samples and more than half of beef and veal sausage samples had
Enterobacteriaceae counts 2: log 4 cfu/g. The majority of pork, beef and veal sausage
samples also harbored coliforms. Furthermore, more than 40% of veal sausage
samples had coliform counts 2:log 4 cfu/g. On the other hand, coli forms were rarely
detected in chicken sausage samples. Enterococci were encountered in 60% of pork,
100% of beef and in more than 70% of veal and chicken sausage samples with counts
ranging from log 2 to log 6 cfu/g. About 26% of pork, 60% of beef and 38% of veal
sausage samples had Staphylococcus counts 2:log 5 cfu/g. All sausage samples
harbored LAB and more than 73% of pork, 60% of beef and about 40% of veal
sausage samples had counts 2:log 7 cfulg. Over 86% of pork, 93% of beef, 38% of
veal and 31 % of chicken sausage samples had yeast counts 2: log 4 cfulg.
In the case of large diameter sausages or mortadellas, about 53% of pork, 48% of veal
and 40% of chicken mortadella samples had aerobic mesophilic counts 2: log 5 cfu/g,
thus exceeded the typical aerobic mesophilic count value set for ready-to-eat foods.
Enterobacteriaceae were encountered in more than 60% of pork, 50% of veal and 45%
of chicken mortadella samples with counts between log 2 and log 4 cfu/g. More than
50% of pork and about 33% of veal and 40% of chicken mortadella samples had also
coliform counts between log 2 and log 4cfu/g. The majority of large diameter
sausages harbored enterococci and staphylococci. LAB were encountered in all
mortadella samples and 40% of pork and more than 30% of veal and chicken
mortadella samples had counts :::Iog 6 cfu/g. The majority of mortadella samples
contained yeasts and more than 45% of pork, 40% of veal and 30% of chicken
mortadella samples had counts::: log 4 cfu/g.
The aerobic mesophilic flora of both small and large diameter sausages was
dominated by Gram-positive organisms, with Bacillus being the most dominant
species in both types of sausages. Salmonel/a was isolated from four (1.9%) samples
consisting of two small diameter sausages and two mortadellas.
During aerobic storage of small diameter sausage samples and sliced mortadella
samples at ambient temperature, both types of sausages spoiled within three to four
days. At refrigeration storage, small diameter sausages spoiled within 12 to 16 days
and mortadella samples spoiled within 12 to 20 days of storage. Spoilage in small
diameter sausage samples was manifested as slime formation and off-odor
development whereas spoilage in sliced mortadella samples was manifested as green
discoloration and off-odor development.
In general, the majority of sausage samples investigated in this study had high
microbial load. Time temperature abuse during processing or post-cooking
contamination due to improper handling of the products or inadequate storage
conditions or a combination of these factors may contribute to high microbial counts.
Furthermore, the absence of microbiological control system or the end product, the
raw material, or the other ingredients, at any stage of production and the poor sanitalY
condition of some processing plants revealed inadequacies conceming quality and
safety of these products.
Key words/ phrases: Addis Ababa, Frankfurters, mortadella, quality, safety,
Salmonel/a, sausage, supermarket
Description
Keywords
Biology